Hi All, Just had a 14kW array installed KH10 inverter and EP12 battery. It was turned on at 14:30 on Monday the 9th so we've not had a lot of sun to test under yet. Two behaviours I'm a bit unsure of.
First, the battery is set to minimum SOC of 10%, when it gets to 10% it charges up to 15% off the grid and then discharges down to 10% and repeat in cycles.
Second, When we do have brief gaps in the cloud and get generation the amount generated from solar, discharged from batter and imported from grid is often higher than usage For instance it currently reads
Solar 323W, Battery 169W Discharging, Grid 7W importing. Home 247W usage. Which seems to be 252W too much power usage. This is true at several points.
Whilst the weather is poor it’s better to put some grid charge into the battery, particularly if you have access to a low overnight tariff - the inverter essentially runs off battery when there is little solar, and whilst it doesn’t consume a lot of power it is responsible for the cycling you are seeing when the battery reaches minsoc.
The information you are looking at is not real time and as loads are dynamic it only really gives a guide as to what the system is doing, your energy statistics (power over time) tell you the real story. But I think the difference you are looking at are system losses, without much sun the system is running at it’s most in-efficient and there will be conversion losses from solar and battery from DC to AC, plus losses in the battery through battery chemistry particularly whilst it’s cylcing like that - the losses become relatively insignificant when you have lots of sun or high loads.
Assuming you are in the UK, February has been dismal so far, over 50% solar less compared to last year, but the days are starting to get longer and the suns elevation is increasing so it won’t be long now (the solar forecast for Saturday is looking good).
The information you are looking at is not real time and as loads are dynamic it only really gives a guide as to what the system is doing, your energy statistics (power over time) tell you the real story. But I think the difference you are looking at are system losses, without much sun the system is running at it’s most in-efficient and there will be conversion losses from solar and battery from DC to AC, plus losses in the battery through battery chemistry particularly whilst it’s cylcing like that - the losses become relatively insignificant when you have lots of sun or high loads.
Assuming you are in the UK, February has been dismal so far, over 50% solar less compared to last year, but the days are starting to get longer and the suns elevation is increasing so it won’t be long now (the solar forecast for Saturday is looking good).
Congrats!datamonkey wrote: ↑Wed Feb 11, 2026 10:37 am Hi All, Just had a 14kW array installed KH10 inverter and EP12 battery. It was turned on at 14:30 on Monday the 9th so we've not had a lot of sun to test under yet. Two behaviours I'm a bit unsure of.
And I would say you are UK resident, so I am thinking you will love this coming Saturday.
You BMS inside your battery is probably still in dire need of calibration with your EP12 being so new, so it might be doing a charge to protect the low cell Voltages. It can also do this if the battery pack is cold to protect itself, but not likely at the moment.datamonkey wrote: ↑Wed Feb 11, 2026 10:37 am First, the battery is set to minimum SOC of 10%, when it gets to 10% it charges up to 15% off the grid and then discharges down to 10% and repeat in cycles.
I used to have this behaviour with the older FW versions (at least this is what I attribute this to, as I had same "issue" of missing power) not tallying up to zero.datamonkey wrote: ↑Wed Feb 11, 2026 10:37 am Second, When we do have brief gaps in the cloud and get generation the amount generated from solar, discharged from batter and imported from grid is often higher than usage For instance it currently reads
Solar 323W, Battery 169W Discharging, Grid 7W importing. Home 247W usage. Which seems to be 252W too much power usage. This is true at several points.
Your FW versions might need updating for several components, I have attached a video here that shows you some solar activity, and you will see that everything tallies up to zero. You might also observe that I have 5 second refresh as you can see in top right countdown, quick way to know if you are up to date or not.
You can check your firmware versions for all your component in the App, by pressing Device at the bottom of your screen, and when you press on an item, you will see a Serial Number you can click on, pressing this reveals current loaded FW
Yes, I'm in the UK and cannot wait till Saturday. Even with today's cloud cover I'm getting periods of charging the battery from solar which is nice. Saturday is going to be huge.
We don't currently have a low overnight tariff, waiting for British Gas to give us an MPAN for our SEG and then looking at whether switching to Ocopus Flux or intelligent flux.
My app is definitely on an older version because I'm only getting the 3-5 minute updates rather than 5 second updates. But even so looking at the data It would be more right if only 25% of the solar was getting through.Hopefully it is just reporting lag because looking at losses when I'm generating 498W DC I'm pushing 453W AC. Which seems right to me.
I'll give the battery a week or so to stabilise and then I might lift the SOC floor to 15%.
We don't currently have a low overnight tariff, waiting for British Gas to give us an MPAN for our SEG and then looking at whether switching to Ocopus Flux or intelligent flux.
My app is definitely on an older version because I'm only getting the 3-5 minute updates rather than 5 second updates. But even so looking at the data It would be more right if only 25% of the solar was getting through.Hopefully it is just reporting lag because looking at losses when I'm generating 498W DC I'm pushing 453W AC. Which seems right to me.
I'll give the battery a week or so to stabilise and then I might lift the SOC floor to 15%.
Roll on Saturday for sure.
I am on Octopus Intelligent Go as have EV and compatible charger... you ***might*** be able to join Octopus Go as it was just a simple tick a box to say you have an EV, though they may have changed rules recently as they are clamping down.
Check App version, pressing Me on bottom right will show you.
Here is a list of the minimum software levels for App/Inverter and Datalogger https://fox-ess.tech/5-second-live-ener ... d-devices/
If you are behind, and odds are you will be, then send email to service.uk@fox-ess.com and give the Serial number for the items you want updating, or you can ask your installer, some are good at helping... others can be lagging.
You could raise the min SoC to 15%, but you are removing capacity off your plate.. if you do decide to increase values, make sure to once a month discharge down to 10% and back to 100% as this calibrates the end points and increases the reported SoC more accurately.
I am on Octopus Intelligent Go as have EV and compatible charger... you ***might*** be able to join Octopus Go as it was just a simple tick a box to say you have an EV, though they may have changed rules recently as they are clamping down.
Check App version, pressing Me on bottom right will show you.
Here is a list of the minimum software levels for App/Inverter and Datalogger https://fox-ess.tech/5-second-live-ener ... d-devices/
If you are behind, and odds are you will be, then send email to service.uk@fox-ess.com and give the Serial number for the items you want updating, or you can ask your installer, some are good at helping... others can be lagging.
You could raise the min SoC to 15%, but you are removing capacity off your plate.. if you do decide to increase values, make sure to once a month discharge down to 10% and back to 100% as this calibrates the end points and increases the reported SoC more accurately.